1. Used on an invitation to request a response

Encyclopedia: RSVP

• space probe
• space program
• space rocket
• space shuttle
• space sickness
• space station
• space travel
• space vehicle
• space writer
• space-reflection symmetry
• space-time
• space-time continuum
• spacecraft
• spacecraft clock time
• spacecraft event time
• spaced
• spaced-out
• spacefaring
• spaceflight
• spaceless
• spaceman
• spacer
• spaceship
• spacesuit
• spacewalk